Nucleate pool boiling heat transfer characteristics of refrigerant/nanolubricant mixture with surfactant

The objective of this paper is to investigate the nucleate pool boiling heat transfer characteristics of refrigerant/nanolubricant mixture with surfactant. In the experiments, three types of surfactants including SDS, CTAB and Span-80 were used. Nanolubricant was formed from Cu nanoparticles and oil VG68. The results show that, the ratio of heat transfer coefficient of refrigerant/nanolubricant mixture with surfactant to that without surfactant (defined as surfactant impact factor, SIF) are within 0.85–1.58, 0.73–1.31, and 0.68–1.24 for SDS, CTAB and Span-80, respectively. The values of SIF increase with the increase of surfactant concentration and then decrease, and increase with the decrease of surfactant molecular weight, nanolubricant concentration and heat flux. A nucleate pool boiling heat transfer correlation for refrigerant/nanolubricant mixture was proposed, and it agrees well with the experimental data of refrigerant/nanolubricant mixture with surfactant and that without surfactant.

► Effect of surfactant on pool boiling of refrigerant/nanolubricant was studied. ► The values of SIF are in the order of SDS > CTAB > Span-80. ► SIF increases with the decrease of nanolubricant concentration and heat flux. ► Maximal SIF increases with increasing nanolubrciant concentration. ► A general correlation for refrigerant/nanolubricant mixture was proposed.